In optical communication systems, non-linear optical effects are known to degrade the quality of transmission along optical fiber and reduce the transmission distance. These non-linear effects, which include four-wave mixing (FWM), self-phase modulation (SPM), cross-phase modulation (XPM), modulation instability (MI), stimulated Brillouin scattering (SBS) and stimulated Raman scattering (SRS), particularly cause distortion in high power systems. Group velocity dispersion also provides a limitation to quality transmission of optical signals across long distances. Group velocity dispersion broadens an optical pulse during its transmission across long distances. Dispersion of an optical pulse, though, can be reduced by decreasing the spacing between regenerators in a communications system, but this approach is costly. Another known solution for counteracting dispersion is the method of adding suitable dispersion compensating devices, such as gratings or dispersion compensating fibers, to the telecommunication system. This solution is effective but adds cost.
One solution to overcome the effects of dispersion in optical communications system without adding substantial cost has been through the use of soliton pulses; particular types of RZ (Return-to-Zero) modulation signals that maintain their pulse width over longer distances by balancing the effects of group velocity dispersion with the non-linear phenomenon of self-phase modulation. A possible problem that arises in the transmission of solitons though, is that a conventional optical transmission fiber is lossy, which causes the peak power of the soliton pulse to decrease exponentially along the length of the fiber between optical amplifiers, therefore disrupting the balance between nonlinearity and dispersion responsible for soliton existence. A solution to this problem is to use dispersion-compensated (DC) solitons, such that pulses are allowed to broaden but only within the limit of the distance between pulses. This regime is achieved by the use of dispersion compensating devices placed in the optical communications path according to specific rules. Any regime that will permit pulse broadening beyond the pulse period is believed to result in inferior performance relative to the above-mentioned technique.